Triple clutch multi-speed transmission

ABSTRACT

A transmission is disclosed having a planetary gear set with three input torque-transmitting mechanisms, such as friction clutches, to achieve torque flow through the planetary gear set to a countershaft gearing arrangement. The transmission includes an input member, an output member, a planetary gear set, an input clutch assembly having three input clutches and a countershaft gearing arrangement. The countershaft gearing arrangement is operatively connected with the planetary gear set and includes: at least three co-planar intermeshing gears, first and second countershafts, a first intermediate shaft and a second intermediate shaft concentric with the first intermediate shaft.

TECHNICAL FIELD

The invention relates to a multi-speed transmission having a tripleinput clutch selectively connectable to a planetary gear set and acountershaft gearing arrangement.

BACKGROUND

A typical multi-speed, dual clutch transmission uses a combination oftwo friction clutches and several dog clutch/synchronizers to achieve“power-on” or dynamic shifts by alternating between one friction clutchand the other, with the synchronizers being “pre-selected” for theoncoming ratio prior to actually making the dynamic shift. “Power-on”shifting means that torque flow from the engine need not be interruptedprior to making the shift. This concept typically uses countershaftgears with a different, dedicated gear pair or set to achieve eachforward speed ratio (with the exception of being able to achieve adirect drive ratio in a rear wheel drive application). Accordingly, thetotal number of gears required in this typical design is two times thenumber of forward speeds, plus three for reverse. This necessitates alarge number of required gear pairs, especially in transmissions thathave a relatively large number of forward speed ratios. Thus, a needexists for a more compact efficient transmission that utilizes gearpairs.

SUMMARY

A transmission is provided having a planetary gear set with triple inputtorque-transmitting mechanism, such as friction clutches, to achievetorque flow through the planetary gear set to a countershaft gearingarrangement. The transmission includes an input member, an outputmember, a planetary gear set, a triple input clutch assembly having afirst, second and third torque-transmitting mechanisms and acountershaft gearing arrangement.

The planetary gear set has first, second and third members. The first,second and third torque-transmitting mechanisms of the triple inputclutch assembly each are selectively engageable to connect the inputmember with a respective different one of the members of the planetarygear set.

The countershaft gearing arrangement is operatively connected with theplanetary gear set and includes: three sets of co-planar intermeshinggears, a first intermediate shaft and a second intermediate shaft, aplurality of synchronizers and first and second countershafts. The firstintermediate shaft is connected for common rotation with the sun gearmember of the planetary gear set. The second intermediate shaft isconnected for common rotation with the carrier member of the planetarygear set.

The first and second countershafts are radially offset from andtypically parallel to the intermediate shafts. The plurality ofsynchronizers are selectively engagable to connect selected ones of thegears of the co-planar gear sets with selected ones of said shafts forcommon rotation to thereby transfer torque from the planetary gear setto the output members along the shafts and the sets of co-planarintermeshing gears.

Each of the countershafts has a countershaft transfer gear rotationallyfixed to the respective countershaft. The countershaft transfer gearseach mesh with an output transfer gear that is connected to the outputmember.

The planetary gear set may be a beveled gear set, a simple pinion or adouble pinion (compound) planetary gear set.

In another aspect of the invention, a reverse torque ratio may beachieved by utilizing a brake that selectively connects the ring gear ofthe planetary gear set to a stationary member to obtain a reverse torqueratio, thus eliminating the need for a dedicated set of intermeshinggears.

Thus, the present invention reduces the number of layshaft gearsrequired for a given number of different gear states by “re-using” someor all of the physical gears in more than one gear state.

The above features and advantages and other features and advantages ofthe present invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of an embodiment of an eight speedtransmission in accordance with the present invention;

FIG. 2 is a truth table listing the engaged torque-transmittingmechanisms and synchronizers for selected torque ratios achieved by theeight speed transmission of FIG. 1;

FIG. 3 is a schematic representation of an embodiment of a nine speedtransmission in accordance with the present invention; and

FIG. 4 is a truth table listing the state of engagement of thetorque-transmitting mechanisms and synchronizers for selected torqueratios achieved by the nine speed transmission of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, wherein like reference numbers refer to likecomponents, in FIG. 1 a multi-speed transmission 10 is depicted. Thetransmission 10 includes an input member 12 and output member 14. In thepresent embodiment, input member 12 and output member 14 are shafts, andwill be referred to as such. Those skilled in the art will appreciatethat the input and output members 12, 14 may be components other thanshafts. The input shaft 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft 14 is continuously connected with the final drive unit (notshown).

Transmission 10 includes a countershaft gearing arrangement 16 thatincludes intermediate shafts, a countershaft, co-planar intermeshinggear sets and selectively engagable synchronizers as will be describedherein. For example, the countershaft gearing arrangement 16 includes afirst intermediate shaft 18 and a second intermediate shaft 20. Firstand second intermediate shafts 18, 20 are sleeve shafts that areconcentric with the input shaft 12. The countershaft gearing arrangement16 further includes a first countershaft 24 and a second countershaft26. Countershaft 24 is both spaced apart from and parallel with inputshaft 12 and intermediate shafts 18 and 20. Countershaft 26 is bothspaced apart from and parallel with input shaft 12 and intermediateshafts 18 and 20.

A planetary gear set 28, which is a compound planetary gear set, isconnected between the input shaft 12 and the output shaft 14. Theplanetary gear set 28 includes sun gear member 30 connected for commonrotation with the first intermediate shaft 18, a ring gear member 32 anda carrier member 34 which rotatably supports a first set of pinion gears36 and a second set of pinion gears 38. First set of pinion gears 36intermesh with both sun gear member 30 and the second set of piniongears 38. Second set of pinion gears 38 intermesh with both ring gearmember 32 and the first set of pinion gears 36.

The countershaft gearing arrangement 16 also includes co-planar,intermeshing gear sets 40, 50 and 60. Gear set 40 includes gears 42, 44and 46. Gear 42 is connected for common rotation with secondintermediate shaft 20 and intermeshes with gears 44 and 46. Gear 44 isrotatable about and selectively connectable with the first countershaft24. Gear 46 is rotatable about and selectively connectable with thesecond countershaft 26.

Gear set 50 includes co-planar intermeshing gears 52, 54 and 56. Gear 52is connected for common rotation with the first intermediate shaft 18and intermeshes with gears 54 and 56. Gear 54 is rotatable about andselectively connectable with the first countershaft 24. Gear 56 isrotatable about and selectively connectable with the second countershaft26.

Gear set 60 includes co-planar intermeshing gears 62 and 64. Gear 62 isconnected for common rotation with the first intermediate shaft 18 andintermeshes with gear 64. Gear 64 is rotatable about and selectivelyconnectable with the second countershaft 26.

Further, a first countershaft transfer gear 66 is rotatably fixed andconnected for common rotation with the first countershaft 24. A secondcountershaft transfer gear 68 is rotatably fixed and connected forcommon rotation with the second countershaft 26. First countershafttransfer gear 66 and the second countershaft transfer gear 68 are eachconfigured to mesh with an output transfer gear 69. The output transfergear 69 is co-planar with first and second countershaft transfer gears66, 68. However, the first countershaft transfer gear 66 and the secondcountershaft transfer gear 68 do not mesh with each other. The outputtransfer member 69 is attached and rotatably drives output shaft 14.Accordingly, torque transmitted to countershaft 24 is transferred totransfer gear 66 and on to output shaft 14 via output transfer gear 69and torque transmitted to countershaft 26 is transferred to transfergear 68 and on to output shaft 14 via output transfer gear 69.

The transmission 10 includes a triple input clutch or assembly 70 havingthree torque-transmitting mechanisms or devices including a first inputclutch 72, second input clutch 74 and third input clutch 76. Tripleinput clutch or assembly 70 has a clutch housing 78 fixedly connected tothe input shaft or member 12. Accordingly, first input clutch 72 isselectively engagable to connect the input shaft 12 with the ring gearmember 32. Second input clutch 74 is selectively engagable to connectthe input shaft 12 with the carrier member 34 and second intermediateshaft 20. Third input clutch 76 is selectively engagable to connect theinput shaft 12 with the sun gear member 30 and first intermediate shaft18.

Additionally, transmission 10 provides a brake member 80. Brake member80 is selectively engagable to connect ring gear member 32 to astationary member such as the transmission housing 82 to restrictrotation of the ring gear member 32.

The transmission 10 further includes a plurality of selectivelyengagable synchronizers 90, 92, 94, 96 and 98. Synchronizer 90 isselectively engagable to connect gear 44 with first countershaft 24 forcommon rotation therewith. Synchronizer 92 is selectively engagable toconnect gear 46 with second countershaft 26 for common rotationtherewith. Synchronizer 94 is selectively engagable to connect gear 54with first countershaft 24 for common rotation therewith. Synchronizer96 is selectively engagable to connect the gear 56 to secondcountershaft 26 for common rotation therewith. Synchronizer 98 isselectively engagable to connect the gear 64 to second countershaft 26for common rotation therewith.

The transmission 10 is capable of transmitting torque from the inputshaft 12 to the output shaft 14 in at least eight forward torque ratiosand one reverse torque ratio as indicated in the truth table of FIG. 2.Each of the forward torque ratios and the reverse torque ratio isattained by engagement of one of the first, second, thirdtorque-transmitting mechanisms or input clutches 72, 74, 76, brake 80and one or more of the synchronizers 90, 92, 94, 96 and 98. Thoseskilled in the art will readily understand that a different speed ratiois associated with each torque ratio. Thus, eight forward speed ratiosmay be attained by the transmission 10.

To establish the reverse torque ratio (Gear State Rev 1), the inputclutches, brake and synchronizers are selected as set forth in the tableof FIG. 2. More specifically, input clutch 74, brake 80 and synchronizer94 are engaged. The input clutch 74 connects the carrier member 34 withthe input shaft 12. Synchronizer 94 connects gear 54 for common rotationwith first countershaft 24. Brake 80 connects ring gear 32 withtransmission housing 82 for braking and preventing the rotation of ringgear 32. Torque is thus transferred from the input shaft 12 through thesun gear member 30 to first intermediate shaft 18 to gear 52. Torque istransferred from gear 52 to first countershaft 24 through synchronizer94. Torque is then transferred from first countershaft 24 to the firstcountershaft transfer gear 66. First countershaft transfer gear 66transfers the torque to the output shaft 14 via the output transfer gear69.

A first forward torque ratio (Gear State 1st in the truth table of FIG.2), is achieved by engaging the input clutch 76 and synchronizer 94. Theinput clutch 76 connects the sun gear member 30 with the input shaft 12.Synchronizer 94 connects gear 54 for common rotation with firstcountershaft 24. Torque is thus transferred from the sun gear member 30to first intermediate shaft 18 to gear 52. Torque is transferred fromgear 52 to first countershaft 24 through synchronizer 94. Torque is thentransferred from first countershaft 24 to the first countershafttransfer gear 66. First countershaft transfer gear 66 transfers thetorque to the output shaft 14 via the output transfer gear 69.

A subsequent forward torque ratio, indicated as Gear State 2nd in FIG.2, is established by engagement of input clutch 74 and synchronizer 90.The input clutch 74 connects the carrier member 34 with the input shaft12. Synchronizer 90 connects gear 44 for common rotation with firstcountershaft 24. Torque is transferred from the input shaft 12 to thecarrier member 34 via the engaged input clutch 74. Torque then flowsfrom the carrier member 34 to second intermediate shaft 20. Torque istransferred from second intermediate shaft 20 to gear 42. Torque istransferred from gear 42 to gear 44 and from synchronizer 90 to firstcountershaft 24. Torque is then transferred from first countershaft 24to the first countershaft transfer gear 66. First countershaft transfergear 66 transfers the torque to the output shaft 14 via the outputtransfer gear 69.

The subsequent torque ratio, indicated as Gear State 3rd in the truthtable of FIG. 2, is established by the engagement of the input clutch 72and synchronizers 90 and 96. The input clutch 72 connects the ring gear32 with the input shaft 12. Synchronizer 96 connects gear 56 for commonrotation with second countershaft 26. Torque is transferred from theinput shaft 12 to the ring gear 32 via the engaged input clutch 72.Torque then flows from the ring gear 32 to carrier member 34. Torque istransferred from carrier member to sun gear 30 and to secondintermediate shaft 20. Torque is transferred from sun gear 30 to gear 52via first intermediate shaft 18 and to gear 42 from second intermediateshaft 20. First intermediate shaft 18 transfers the torque to gear 52.Gear 42 transfers the torque to gear 44 and gear 52 transfers the torqueto gear 54. Gear 44 transfers the torque to first countershaft 24 viasynchronizer 90 and gear 54 transfers the torque to second countershaft26 via synchronizer 96. Torque is then transferred from firstcountershaft 24 to the first countershaft transfer gear 66 from firstcountershaft 24 to the first countershaft transfer gear 66 and fromsecond countershaft 26 to the second countershaft transfer gear 68.First and second countershaft transfer gears 66, 68 transfer the torqueto the output shaft 14 via the output transfer gear 69.

The next subsequent forward torque ratio, indicated as Gear State 4th inthe truth table of FIG. 2, is established with the engagement of theinput clutch 76 and synchronizer 96. The input clutch 76 connects thesun gear 30 with the input shaft 12. Synchronizer 96 connects gear 56for common rotation with second countershaft 26. Torque is transferredfrom the input shaft 12 to the sun gear 30 via the engaged input clutch76. Torque then flows from the sun gear 30 to gear 52 via firstintermediate shaft 18. Gear 52 transfers the torque to gear 54. Gear 54transfers the torque to second countershaft 26 via synchronizer 96.Torque is then transferred from second countershaft 26 to the secondcountershaft transfer gear 68. Second countershaft transfer gear 68transfers the torque to the output shaft 14 via the output transfer gear69.

A subsequent forward torque ratio indicated as Gear State 5th in FIG. 2,is established with the engagement of input clutch 72 and synchronizers92 and 96. The input clutch 72 connects the ring gear 32 with the inputshaft 12. Synchronizer 92 connects gear 46 for common rotation withsecond countershaft 26. Synchronizer 96 connects gear 56 for commonrotation with second countershaft 26. Torque is transferred from theinput shaft 12 to the ring gear 32 via the engaged input clutch 72.Torque then flows from the ring gear 32 to carrier member 34. Torque istransferred from carrier member 34 to gear 42 via second intermediateshaft 20 and to sun gear 30. Sun gear 30 transfers the torque to gear 52via first intermediate shaft 18. Gear 42 transfers the torque to gear 46and gear 52 transfers the torque to gear 56. Gear 46 transfers thetorque to second countershaft 26 via synchronizer 92 and gear 56transfers the torque to second countershaft 26 via synchronizer 96.Torque is then transferred from second countershaft 26 to the outputshaft 14. Torque is then transferred from second countershaft 26 to thesecond countershaft transfer gear 68. Second countershaft transfer gear68 transfers the torque to the output shaft 14 via the output transfergear 69.

A subsequent forward torque ratio indicated as Gear State 6th in thetruth table of FIG. 2 is established with the engagement of input clutch74 and synchronizer 92. The input clutch 74 connects the carrier member34 with the input shaft 12. Synchronizer 92 connects gear 46 for commonrotation with second countershaft 26. Torque is transferred from theinput shaft 12 to the carrier member 34 via the engaged input clutch 74.Torque then flows from the carrier member to gear 42 via secondintermediate shaft 20. Gear 42 transfers the torque to gear 46. Gear 46transfers the torque to second countershaft 26 via synchronizer 92.Torque is then transferred from second countershaft 26 to the secondcountershaft transfer gear 68. Second countershaft transfer gear 68transfers the torque to the output shaft 14 via the output transfer gear69.

A subsequent forward torque ratio indicated as Gear State 7th in FIG. 2,is established with the engagement of input clutch 72 and synchronizers92 and 98. The input clutch 72 connects the ring gear 32 with the inputshaft 12. Synchronizer 92 connects gear 46 for common rotation withsecond countershaft 26. Synchronizer 98 connects gear 64 for commonrotation with second countershaft 26. Torque is transferred from theinput shaft 12 to the ring gear 32 via the engaged input clutch 72.Torque then flows from the ring gear 32 to carrier member 34. Torque istransferred from carrier member 34 to gear 42 via second intermediateshaft 20 and to sun gear 30. Sun gear 30 transfers the torque to gear 62via first intermediate shaft 18. Gear 42 transfers the torque to gear 46and gear 62 transfers the torque to gear 64. Gear 46 transfers thetorque to second countershaft 26 via synchronizer 92 and gear 64transfers the torque to second countershaft 26 via synchronizer 98.Torque is then transferred from second countershaft 26 to the secondcountershaft transfer gear 68. Second countershaft transfer gear 68transfers the torque to the output shaft 14 via the output transfer gear69.

The next subsequent forward torque ratio, indicated as Gear State 8th inthe truth table of FIG. 2, is established with the engagement of theinput clutch 76 and synchronizer 98. The input clutch 76 connects thesun gear 30 with the input shaft 12. Synchronizer 98 connects gear 64for common rotation with second countershaft 26. Torque is transferredfrom the input shaft 12 to the sun gear 30 via the engaged input clutch76. Torque then flows from the sun gear 30 to gear 62 via firstintermediate shaft 18. Gear 62 transfers the torque to gear 64. Gear 64transfers the torque to second countershaft 26 via synchronizer 96.Torque is then transferred from second countershaft 26 to the secondcountershaft transfer gear 68. Second countershaft transfer gear 68transfers the torque to the output shaft 14 via the output transfer gear69.

The present invention contemplates that downshifts follow essentiallythe reverse sequence of the corresponding upshift (as described above),and several power-on skip-shifts are possible.

Referring now to FIG. 3 a nine speed transmission 100 is depictedaccording to the principles of the invention. The transmission 100 hasthe same components as described previously with respect to transmission10 and as indicated in FIG. 3 with like reference numbers. However,transmission 100 has a different arrangement for co-planar gear set 60,herein referenced as co-planar gear set 60′. Co-planar gear set 60′ isnow located furthest from input clutch 70. More specifically, gear set60′ includes co-planar intermeshing gears 62′ and 64′. Gear 62′ isconnected for common rotation with the first intermediate shaft 18 andintermeshes with gear 64. Gear 64 is rotatable about and selectivelyconnectable with the first countershaft 24 instead of secondcountershaft 26, as described above with respect to transmission 10.Synchronizer 98′ selectively engages gear 64′ to first countershaft 24for common rotation therewith instead of selectively connecting gear 64to second countershaft 26, as described above with respect totransmission 10.

The transmission 100 is capable of transmitting torque from the inputshaft 12 to the output shaft 14 in at least nine forward torque ratiosand one reverse torque ratio as indicated in the truth table of FIG. 4.Each of the forward torque ratios and the reverse torque ratio isattained by engagement of one of the first, second, thirdtorque-transmitting mechanisms or input clutches 72, 74, 76, brake 80and one or more of the synchronizers 90, 92, 94, 96 and 98 as indicatedby an “X” in the columns of the truth table of FIG. 4. Those skilled inthe art will readily understand that a different speed ratio isassociated with each torque ratio. Thus, nine forward speed ratios maybe attained by the transmission 100.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. A transmission comprising: an input member; an output member; aplanetary gear set having first, second and third members; a clutchassembly having a first, a second and a third torque-transmittingmechanism each selectively engageable to connect the input member with arespective different one of the members of the planetary gear set; afirst intermediate shaft connected for common rotation with the firstmember of said planetary gear set; a second intermediate shaft connectedfor common rotation with the second member of said planetary gear set,wherein the second intermediate shaft is concentric with the firstintermediate shaft; a first countershaft radially offset from theintermediate shafts; a second countershaft radially offset from theintermediate shafts; a first countershaft transfer gear connected forcommon rotation with the first countershaft and in communication withthe output member to transfer torque from the first countershaft to theoutput member; a second countershaft transfer gear connected for commonrotation with the second countershaft and in communication with theoutput member to transfer torque from the second countershaft to theoutput member; three co-planar intermeshing gear sets, wherein one ofthe gears of only one of the three co-planar intermeshing gear sets isfixed for common rotation with one of the intermediate shafts andwherein one of the gears of the two other co-planar intermeshing gearsets is fixed for common rotation with the other of the intermediateshafts; and a plurality of synchronizers, wherein at least one of theplurality of synchronizers is selectively engagable to connect at leastone of the gears of the at least three co-planar intermeshing gear setswith at least one of the first and second countershafts for commonrotation therewith, thereby transferring torque from the planetary gearset to at least one of the first and second countershaft transfer gearsthrough at least one of the intermediate shafts and at least one of thesets of co-planar intermeshing gear sets.
 2. The transmission of claim 1wherein the first member of the planetary gear set is a sun gear, thesecond member of the planetary gear set is a planet carrier member andthird member of the planetary gear set is a ring gear.
 3. Thetransmission of claim 2 wherein the planet carrier member rotatablysupports a first and second set of planet gears and wherein the firstset of planet gears intermeshes with the sun gear and the second set ofplanet gears and the second set of planet gears intermeshes with thering gear and the first set of planet gears.
 4. The transmission ofclaim 2 wherein the first intermediate shaft is connected for commonrotation with sun gear of the planetary gear set.
 5. The transmission ofclaim 2 wherein the second intermediate shaft is connected for commonrotation with the planet carrier member of said planetary gear set. 6.The transmission of claim 2 wherein the first torque-transmittingmechanism is selectively engageable to connect the input member with thering gear of the planetary gear set, the second torque-transmittingmechanism is selectively engageable to connect the input member with theplanet carrier of the planetary gear set and the thirdtorque-transmitting mechanism is selectively engageable to connect theinput member with the sun gear of the planetary gear set.
 7. Thetransmission of claim 1 wherein two of the three co-planar intermeshinggears each include a first gear in mesh with a second and third gear. 8.The transmission of claim 7 wherein one of the three co-planarintermeshing gears includes a first gear in mesh with a second gear. 9.(canceled)
 10. The transmission of claim 8 wherein the second gears oftwo of the three co-planar intermeshing gear sets are selectivelyengageable with the first countershaft and the second gear of theremaining one of the three co-planar intermeshing gear sets isselectively engageable with the second countershaft.
 11. Thetransmission of claim 1 wherein the plurality of synchronizers furtherincludes a first synchronizer for selectively connecting a second gearof a first of the three co-planar intermeshing gear sets with the firstcountershaft.
 12. The transmission of claim 11 wherein the plurality ofsynchronizers further includes a second synchronizer for selectivelyconnecting a third gear of the first of the three co-planar intermeshinggear sets with the second countershaft.
 13. The transmission of claim 12wherein the plurality of synchronizers further includes a thirdsynchronizer for selectively connecting a second gear of a second of thethree co-planar intermeshing gear sets with the first countershaft. 14.The transmission of claim 13 wherein the plurality of synchronizersfurther includes a fourth synchronizer for selectively connecting athird gear of the second of the three co-planar intermeshing gear setswith the second countershaft.
 15. The transmission of claim 14 whereinthe plurality of synchronizers further includes a fifth synchronizer forselectively connecting a second gear of a third of the three co-planarintermeshing gear sets with the second countershaft.
 16. Thetransmission of claim 1 wherein the output member further includes anoutput transfer gear in mesh with each of the first and secondcountershaft transfer gears.
 17. A transmission comprising: an inputmember; an output member; a planetary gear set having a sun gear, acarrier member and a ring gear, wherein the carrier member rotatablysupports a first and second set of planet gears and wherein the firstset of planet gears intermeshes with the sun gear and the second set ofplanet gears and the second set of planet gears intermeshes with thering gear and the first set of planet gears; a clutch assembly having afirst, a second and a third clutch, wherein the first clutch isselectively engageable to connect the input member with the ring gear ofthe planetary gear set, the second clutch is selectively engageable toconnect the input member with the carrier member of the planetary gearset and the third clutch is selectively engageable to connect the inputmember with the sun gear of the planetary gear set; a first intermediateshaft connected for common rotation with the sun gear of the planetarygear set, wherein the first intermediate shaft is concentric with theinput shaft; a second intermediate shaft connected for common rotationwith the carrier member of the planetary gear set, wherein the secondintermediate shaft is concentric with the first intermediate shaft; afirst countershaft radially offset from the intermediate shafts and incommunication with the output member; a second countershaft radiallyoffset from the intermediate shafts and in communication with the outputmember; a first, second and third co-planar intermeshing gear sets,wherein the first and second co-planar intermeshing gear sets eachhaving a first gear intermeshing with a second and third gear and thirdco-planar intermeshing gear set has a first gear intermeshing withsecond gear, wherein the first gears of the second and third co-planarintermeshing gear sets are fixed for common rotation with the firstintermediate shaft and the first gear of the first co-planarintermeshing gear sets is fixed for common rotation with the secondintermediate shaft; and a plurality of synchronizers, wherein at leastone of the plurality of synchronizers is selectively engagable toconnect at least one of the gears of the first, second and thirdco-planar intermeshing gear sets with at least one of the first andsecond countershafts for common rotation therewith, thereby transferringtorque from the planetary gear set to at least one of the first andsecond countershafts through at least one of the first and secondintermediate shafts.
 18. The transmission of claim 17 wherein theplurality of synchronizers further includes a first synchronizer forselectively connecting the second gear of the first co-planarintermeshing gear sets with the first countershaft.
 19. The transmissionof claim 18 wherein the plurality of synchronizers further includes asecond synchronizer for selectively connecting the third gear of thefirst co-planar intermeshing gear sets with the second countershaft. 20.The transmission of claim 19 wherein the plurality of synchronizersfurther includes a third synchronizer for selectively connecting thesecond gear of the second co-planar intermeshing gear sets with thefirst countershaft.
 21. The transmission of claim 20 wherein theplurality of synchronizers further includes a fourth synchronizer forselectively connecting the third gear of the second co-planarintermeshing gear sets with the second countershaft.
 22. Thetransmission of claim 21 wherein the plurality of synchronizers furtherincludes a fifth synchronizer for selectively connecting the second gearof the third of the co-planar intermeshing gear sets with the secondcountershaft.
 23. The transmission of claim 17 further comprising firstand second countershaft transfer gears, wherein the first countershafttransfer gear is rotatably fixed for common rotation with the firstcountershaft and the second countershaft transfer gear is rotatablyfixed for common rotation with the second countershaft.
 24. Thetransmission of claim 23 wherein the output member further includes anoutput transfer gear in mesh with each of the first and secondcountershaft transfer gears.
 25. A transmission comprising: an inputmember; an output member; a planetary gear set having first, second andthird members; a clutch assembly having a first, a second and a thirdtorque-transmitting mechanism each selectively engageable to connect theinput member with a respective different one of the members of theplanetary gear set; a first intermediate shaft connected for commonrotation with the first member of said planetary gear set; a secondintermediate shaft connected for common rotation with the second memberof said planetary gear set, wherein the second intermediate shaft isconcentric with the first intermediate shaft; a first countershaftradially offset from the intermediate shafts; a second countershaftradially offset from the intermediate shafts; a first countershafttransfer gear connected for common rotation with the first countershaftand in communication with the output member to transfer torque from thefirst countershaft to the output member; a second countershaft transfergear connected for common rotation with the second countershaft and incommunication with the output member to transfer torque from the secondcountershaft to the output member; at least three co-planar intermeshinggear sets, wherein at least one of the gears of the at least threeco-planar intermeshing gear sets is fixed for common rotation with atleast one of the intermediate shafts; and a plurality of synchronizers,wherein at least one of the plurality of synchronizers is selectivelyengagable to connect at least one of the gears of the at least threeco-planar intermeshing gear sets with at least one of the first andsecond countershafts for common rotation therewith, thereby transferringtorque from the planetary gear set to at least one of the first andsecond countershaft transfer gears through at least one of theintermediate shafts and at least one of the sets of co-planarintermeshing gear sets wherein two of the at least three co-planarintermeshing gears each include a first gear in mesh with a second andthird gear.